Ultrasound assessment of cervical length in pregnancy.
Cervical length in high-risk women for preterm birth has to be identified before early second trimester. Sequential evaluations lead to high predictive significance. The mean cervical length at 24 weeks is about 35 mm when measured by transvaginal ultrasound. A short cervix is defined as a cervix that is less than 25 mm and funneling, i.e. ballooning of the membranes into a dilated internal os, but with a closed external os. Factors such as short cervical length, uterine anomaly, previous cervical surgery, multiple gestation and positive fetal fibronectin results are associated with preterm delivery. Serial transvaginal ultrasound examinations during the early second trimester would provide longitudinal changes in the cervical length. The use of 17alpha-hydroxyprogesterone caproate and cerclage has shown to be beneficial in preventing preterm delivery. When combined with other predictors such as occiput position, parity, maternal age and body mass index, cervical length is a useful parameter for predicting the feasibility of labor induction and successful delivery.
Chao
An-Shine
AS
Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Chang Gung University, Tao-Yuan, Taiwan. aschao1295@cgmh.org.tw
Chao
Angel
A
Hsieh
Peter Ching-Chang
PC
D000328:Adult; D023802:Cerclage, Cervical / Q000379:methods; D020070:Cervical Ripening / Q000502:physiology; D002584:Cervix Uteri / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D047928:Premature Birth / Q000517:prevention & control; D012307:Risk Factors; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal; D055815:Young Adult